body{
    width: 100%;
    min-width: 320px;
    max-width: 640px;
    margin: 0 auto;
    font-size: 14px;
    color: #666;
    line-height: 1.5;
    font-family: -apple-system, Helvetica, sans-serif;
    background-color: #f6f6f6;
    height: 2000px;
}
a{
    color: #666;
    text-decoration: none;
}
img{
    vertical-align: middle;
}
/* 顶部 */
.app{
    height: 45px;
}
ul{
    margin: 0;
    padding: 0;
    list-style: none;
}
.app ul li {
    height: 45px;
    background-color: #333;
    float: left;
    line-height: 45px;
    text-align: center;
}
.app ul li:nth-child(1){
    width: 8%;
    font-size: 20px;
    /* text-align: center; */
   
}
.app ul li:nth-child(2){
    width: 10%;
    /* display: inline-block; */

}
.app ul li:nth-child(2) img{
    width: 30px;
    /* text-align: center; */
    /* display: inline-block; */
    vertical-align: middle;

}
.app ul li:nth-child(3){
    width:57%;
    color: aliceblue;
}
.app ul li:nth-child(4){
    width: 25%;
    background-color: #ff4400;
    color: aliceblue;
}
/* 搜索 */
.search_wrap{
    height: 44px;
    position: fixed;
    overflow: hidden;
    width: 100%;
    min-width: 320px;
    max-width: 640px;
}
.search_btn{
    position: absolute;
    top: 0;
    left: 0;
    width: 40px;
    height: 44px;
    color: aliceblue;
    font-size: 20px;
    text-align: center;
    line-height: 44px;
    font-weight:600;

}
.search_login{
    position: absolute;
    top: 0;
    right: 0;
    width: 40px;
    height: 44px;
    text-align: center;
    color: aliceblue;
    line-height: 44px;
}
.search{
    position: relative;
    height: 30px;
    background-color: rgb(255, 255, 255);
    margin: 0 50px;
    border-radius: 15px;
    margin-top: 7px;
}
.jd_icon{
    width: 20px;
    height: 15px;
    position: absolute;
    top: 8px;
    left: 13px;
    /* background-color: pink; */
    background: url(../images/jd-sprites.png) no-repeat;
    background-position: 0% 0%;
    background-size:200px 200px;
}
.jd_icon::after{
    content: '';
    display: block;
    width: 1px;
    height: 15px;
    background-color: #ccc;
    position: absolute;
    right: -8px;
    top: 0;
}
.sou{
    width: 18px;
    height: 15px;
    /* background-color: pink; */
    position: absolute;
    top: 8px;
    left: 50px;
    background: url(../images/jd-sprites.png)no-repeat -81px 0;
    background-size: 200px auto;
}
/* 主体内容 */
/* banner */
.slider img{
    width: 100%;
}
/* ad */
.ad img{
    width: 100%;
}

/* nav导航栏 */
nav{
    padding-top: 5px;
}
nav a {
    float: left;
    width: 20%;
    text-align: center;
}
nav a img{
    width: 40px;
    margin: 10px 0;
}
nav a span{
    display: block;
}